Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/20—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
  • H01B3/22—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils hydrocarbons
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G4/00—Fixed capacitors; Processes of their manufacture
  • H01G4/002—Details
  • H01G4/018—Dielectrics
  • H01G4/20—Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06
  • H01G4/22—Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 impregnated
  • H01G4/221—Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 impregnated characterised by the composition of the impregnant

Definitions

• U.S. Pat. No. 4,111,825 it is disclosed in U.S. Pat. No. 4,111,825 to use, as an electrical insulating oil, a by-product oil in a benzene manufacture process to alkylate benzene with ethylene in the presence of, for example, an aluminum chloride catalyst, and similarly, U.S. Pat. No. 4,568,793 discloses that a by-product oil in an ethyltoluene manufacture process to alkylate toluene with ethylene is used as an electrical insulating oil.
• oil-filled electrical appliances such as oil-filled capacitors recently have a noticeable tendency toward small size and lightweight, and in reply to this tendency, plastic materials for insulators and dielectrics have been developed and are now used together with or in place of conventional insulating papers.
• Electrical insulating oils with which electrical appliances are impregnated also involve various problems in being used together with the above-mentioned plastic materials. That is, conventional electrical insulating oils, for example, refined mineral oils, polybutenes, alkylbenzenes and the like are not satisfactorily applied to plastic materials of polyolefins such as polypropylene, polymethylpentene and polyethylene which are used in the oil-filled electrical appliances. Some of these conventional electrical insulating oils dissolve or swell these plastic materials to deteriorate insulating power of the oil-filled electrical appliances on occasions.
• this invention is directed to an electrical insulating oil composition produced by bringing a by-product oil fraction mainly containing components with boiling points in the range of 260° to 330° C. (atmospheric pressure basis) into liquid-liquid contact with an organic polar solvent.
• the aforesaid by-product oil fraction is formed by first preparing an alkylated product composed of unreacted benzene or unreacted toluene, ethylbenzene or ethyltoluene, polyalkylbenzenes and heavy components by alkylating benzene or toluene with ethylene in the presence of an alkylation catalyst, and then distilling off unreacted benzene or unreacted toluene, ethylbenzene or ethyltoluene and most of polyalkylbenzenes from the alkylated product.
• the foregoing electrical insulating oil composition is such that the ratio of the integrated intensity as chemical shift at 120 to 155 ppm of the spectrum measured by 13 C NMR method to the total integrated intensity at 0 to 155 ppm of the spectrum is 70% or higher. Furthermore, this invention is directed to an electrical appliances impregnated with the above electrical insulating oil composition.
• the above-mentioned alkylation is usually performed in accordance with a liquid phase alkylation process or a gaseous phase alkylation process.
• a Friedel-Crafts catalyst such as aluminum chloride and a Br.0.nsted acid such as sulfuric acid, toluenesulfonic acid and hydrofluoric acid
• a synthetic zeolite for example, ZSM-5 type zeolite such as ZSM-5 and a suitable carrier supporting phosphoric acid are used.
• a reaction temperature is usually in the range of 20° to 180° C. in the case of the liquid phase alkylation process, and it is in the range of 250° to 450° C. in the case of the gaseous phase alkylation process.
• distillation under reduced pressure or atmospheric pressure is carried out to remove, from the alkylated product, unreacted benzene or toluene, aimed ethylbenzene or ethyltoluene, and most of a polyalkylbenzene other than ethyltoluene such as polyethylbenzene or polyethyltoluene, thereby obtaining a by-product oil fraction.
• the by-product which will be treated in this invention mainly contains components having boiling points (atmospheric pressure basis) in the range of 250° to 350° C., preferably 260° to 330° C.
• the by-product oil fraction is supposed to be a hydrocarbon mixture containing partially polyethylbenzene and polyethyltoluene, and additionally containing indane derivatives, diaryl or triarylalkane derivatives and polyalkyl-polyphenyl derivatives, and so forth.
• organic polar solvents include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol and furfuryl alcohol, glycols such as ethylene glycol, propylene glycol, diethylene glycol and triethylene glycol, ketones such as acetone and methyl ethyl ketone, Cellosolves such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, ethers such as furfural, sulfolane, dimethylsulfoxide (DMSO), acetonitrile, N-methylpyrrolidone (NMP) and dimethylformamide (DMF).
• alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol and furfuryl alcohol
• glycols such as ethylene glycol, propylene glycol, diethylene glycol and tri
• the addition of a suitable amount of water to the organic solvent is preferable because of heightening the effect of the abovementioned contact treatment, and the amount of water to be added is in the range of 50 wt % or lower, preferably 40 wt % or lower, with respect to the organic solvent.
• the desired electrical insulating oil of this invention is recovered as an extract. Therefore, after the extraction with the aid of the polar solvent, the desired electrical insulating oil can be recovered by a suitable procedure, for example, by the distillation and the addition of a third component to separate the polar solvent therefrom.
• the liquid-liquid extraction can be carried out by the use of a usual batch type or continuous type counter flow extraction tower, a multi-stage extraction tower or the like. After the liquid-liquid extraction, the used polar solvent is separated and removed in an ordinary manner, thereby obtaining the electrical insulating oil of this invention.
• a composition of the obtained oil depends upon a kind of used polar solvent and other conditions such as an extraction temperature and an amount of the polar solvent with respect to the by-product oil fraction.
• the extraction temperature is in the range of 10° to 150° C.
• the amount of the polar solvent is in the range of 1 to 30 parts by weight per part by weight of the by-product oil fraction.
• the polar solvent is used in an amount of 1 to 30 parts by weight per part by weight of the by-product oil fraction, and in general, 20 or more separation stages are preferably employed under a reduced pressure of 100 mmHg or lower.
• the above-mentioned conditions for the liquid-liquid contact operation should be selected so that the electrical insulating oil may be obtained in which the ratio of the integrated intensity as chemical shift at 120 to 155 ppm of the spectrum measured by 13 C NMR method to the total integrated intensity at 0 to 155 ppm of the spectrum is 70% or higher, preferably 72% or higher.
• the ratio of the integrated intensity as chemical shift at 120 to 155 ppm of the spectrum measured by 13 C NMR method to the total integrated intensity at 0 to 155 ppm of the spectrum is 70% or higher, preferably 72% or higher.
• a conventional solvent purification for the insulating oil is different from that of this invention in that the conventional case intends to prepar a raffinate.
• the conventional purification technique contemplates decreasing the amount of aromatics, but in the liquid-liquid contact of this invention, the amount of aromatics is rather finally increased. Also in this point, the liquid-liquid contact of this invention should be distinguished from the conventional technique.
• a measurement temperature is usually ordinary temperature.
• a fraction which is a sample to be measured is dissolved in deuterated chloroform which is a solvent for the measurement so that the concentration of the fraction may be 10 to 20% by volume.
• a frequency for the measurement can be suitably changed but it is, for example, 67.8 MHz.
• an integrated intensity as chemical shift at 120 to 155 ppm thereof is determined, using tetramethylsilane as standard, and the ratio (%) of the thus obtained value to the total integrated intensity at 0 to 155 ppm of the total spectrum except that of the solvent, is calculated. The calculated value is rounded at the first decimal place.
• the thus prepared electrical insulating oil is then purified, if necessary, and is preferably used as an oil with which capacitors are impregnated.
• the electrical insulating oil of this invention may be mixed with conventional electrical insulating oils, for example, diarylalkane, alkylbiphenyl or alkylnaphthalene in an optional ratio in compliance with uses and other conditions.
• the electrical insulating oil composition of this invention can be employed as an impregnating material to oil-filled electrical appliances such as oil-filled capacitors and oil-filled cables.
• the oil-filled capacitors to which the composition of this invention can be preferably applied are those in which at least a part of dielectric is composed of a plastic material.
• the plastic materials include polyolefins such as polyethylene and polymethylpentene, and a more preferable one is polypropylene.
• the oil-filled capacitors can be manufactured by first winding a polypropylene film together with a metal foil such as an aluminum foil which is a conductor, if necessary, using an insulating paper, and then impregnating the wound material with the above-mentioned electrical insulating oil in an ordinary manner.
• suitable capacitors include oil-filled capacitors manufactured by the other procedure in which a metallized plastic film such as a metallized polypropylene film is wound together with an insulating paper or a plastic film, and is then impregnated with the electrical insulating oil.
• oil-filled capacitors using a plastic material physical properties of the by-product oil fraction which are not always suitable for impregnation are remarkably improved, and hence oil-filled capacitors impregnated with the electrical insulating oil of this invention are excellent in corona discharge properties, low-temperature properties and the like.
• a polar solvent and a by-product oil fraction were mixed with each other in a weight ratio of 1:1, and the mixture was then shaken sufficiently in a separatory funnel and a raffinate was removed therefrom. Afterward, the mixture was washed with n-hexane to recover, as a raffinate, an oil from which the used polar solvent had been removed. This operation was repeated thrice, thereby obtaining an electrical insulating oil.
• a polar solvent and a by-product oil fraction were mixed with each other in a weight ratio of 1:1, and the mixture was then shaken sufficiently in a separatory funnel and a raffinate was removed therefrom. Afterward, the used polar solvent was removed by flash distillation. This operation was repeated thrice, thereby recovering an electrical insulating oil from the by-product oil fraction.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Organic Insulating Materials (AREA)
• Lubricants (AREA)

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Citations (6)

• 1986
  • 1986-11-08 JP JP61265901A patent/JPH088015B2/ja not_active Expired - Lifetime
• 1988
  • 1988-05-03 CA CA000565727A patent/CA1339626C/en not_active Expired - Fee Related
  • 1988-05-06 US US07/191,054 patent/US4967028A/en not_active Expired - Lifetime
  • 1988-05-06 EP EP88107350A patent/EP0340330B1/en not_active Expired - Lifetime

Patent Citations (6)

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